Recording apparatus



Nov. 27, 1945. I} M, TEIN 2,389,827

RECORDING APPARATUS Filed March 2, 1942 2 Sheets$heet 1 INVENTOR.

ATTORNEY.

Nov. 27, 1945. M. STEIN 2,389,827

RECORDING APPARATUS Filed March 2, 1942 2 Sheets-Sheet 2 A TTORNEY.

Patented Nov. 27, 1945 RECORDING APPARATUS Irving M. Stein, Philadelphia, Pa., assignor to Leeds and Northrup Company, Philadelphia, Pa., a corporation of Pennsylvania Application March 2, 1942, Serial 1%. 432,923

2 Claims.

My inventionrelates to systems for recording the magnitudes of one or more conditions, such as pressure, temperature, and the like, and particularly relates to measuring apparatus in which a slide wire or equivalent impedance is adjusted to rebalance an electrical network concurrently with the positioning of a recording element.

In accordance with one aspect of my invention, a rotatable printing element, preferably rigidly connected to the adjustable element of a slide wire or equivalent, comprises a scale against which is intermittently pressed a record sheet or any equivalent record-receiving member to receive a series of symbols, each a reproduction or facsimile of that fraction of the scale which includes or consists of the graduation or marking corresponding with the then existing magnitude of the condition under measurement; preferably, concurrently with printing of each symbol thereon, the record sheet is also pressed against an index, cooperative with the scale, precisely to reproduce on the record the relative positions of the index and the thereto presented portion of the scale; and, when the instrument is of the socalled multi-point" type, one in which a plurality of condition-responsive devices are in succession connected to the measuring circuit, there is printed in association with each symbol, and preferably concurrently therewith, a letter, numeral, or other character identifying the particular condition-responsive device in circuit when that symbol or facsimile was'printed.

In accordance with my invention, upon one portion of a record sheet is traced by a pen or stylus a curve indicating the changes, with time, of the trend of magnitude of a condition, and the aforesaid printing element impresses along a parallel portion of the sheet a series of symbols each precisely indicating, at suitably short intervals, the magnitudes of the condition.

My invention further resides in the features of construction, combination and arrangement hereinafter described and claimed.

For an understanding of my invention, referonce is made to the accompanying drawings in which:

Fig. 1 diagrammatically illustrates the apparatus shown in Fig. 4 in association with a selfbalancing mechanical relay system.

Fig. 2 illustrates the apparatus of Fig. 4 in as- Fig. 5.is a fragmentary view showing, in side elevation, parts appearing in Fig. 4.

Figs, 6 and '7, on an enlarged scale, illustrate details of construction of sheet-feeding mechanism appearing in Fig. 4. v

Referring to the drawings, to the end that disc I or equivalent may be angularly positioned in accordance with the. magnitude of a condition to be measured, its shaft 2 may be connected to a member directly or indirectly responding to the changes in magnitude of the condition; more particularly shaft 2 may-be connected to, .or comprise, th'e controlled shaft of a self-balancing relay mechanism of the type disclosed in Letters Patent 1,935,732 to Squibb; or, shaft 2 may comprise or be connected to the controlled shaft of a high-speed relay system of the type disclosed in Letters Patent 2,113,164 to Williams.

In each of the latter instances, a slide wire or equivalent impedance I2 is mounted for movement in unison with shaft 2 and disc I without interposition of any motion-transmitting element or arrangements such as gearing, linkage, or cable; it is thus assured the position of disc I because of absence of lost-motion or back-lash accurately corresponds, at balance of the measuring network including the slide wire, with the existing magnitude of the condition under measurement. The scale 3, Fig. 2, preferably engraved or embossed upon the front face of disc I, is of angular extent corresponding with the range of adjustment of the slide wire, usually less than 360;

the scale is preferably directly calibrated in units of measurement, for example in degrees of temperature, gallons per second, pounds per square inch, watts, etc.

The record sheet 4, of paper, or equivalent material, is disposed, between the front face of disc I and a pressure block or platen 5. By any suitable, means, block 5 is intermittently or periodically moved to press the record sheet 4 against the scale 3 of disc I to receive an impression of that portion of the scale which includes not only the graduation corresponding with the then existing magnitude of the condition under measurement but also a limited number of graduations on either side thereof. The record strip 4 isadvanced continuously by any suitable means, not shown, with the result the aforesaid movement of block 5 results in transfer to,or impression upon, the record sheet of a series of symbols 8, Fig. 4, each comprising a reproduction of that portion of the scale which corresponded at the time of the printing with the then existing magitude of thecondition under measurement.

In the particular arrangement shown in Fig. 5, for enhanced visibility of the symbol S, a typewriter ribbon or equivalent, may pass between the record strip 4 and scale 3; the inked ribbon 1 may be intermittently or continuously advanced by any suitable means not disclosed.

For precise indication of the magnitudes of the condition, each.symbol includes not only-a por tion of the scale 3 comprehendin the magnitude of the condition, but also a reproduction S of a stationary index cooperative therewith.

As illustrative of an arrangement in which disc I is adjusted by mechanical relay mechanism under control of a galvanometer in a measuring network, reference is made to Fig. 1; the mechanical relay mechanism, of the type disclosed in aforesaid Squibb patent, includes the lamping bars 33, 33 periodically moved relatively to each other to clampthe pointer of galvanometer G between them. While the pointer is so clamped, the feelers 34, 34 are released for movement toward each other to engage opposite sides of the pointer. If the pointer is clamped in position displaced from its null or neutral position, one

.or the other of the feelers, depending upon the sense of deflection of the pointer from null position, engages the driving clutch member 35 and moves it about its pivot 36 with respect to the driven clutch member 31 then out of engagement therewith. Subsequently in a revolution of the constant-speed shaft 38, one or the other of cams 33 engages driving clutch member 35, then in engagement with driven clutch member 31, and

restores it to its horizontal or neutral position and in so doing effects adjustment of slidewirel2 and printing disc I.

By one or more of such cycles of operation (which may require as little as two' seconds for completion), the network N including a condition-responsive device l4, galvanometer G and slidewire I2 is rebalanced after every change in magnitude of the condition. Consequently, from the series of symbols S printed upon record sheet 4, Fig. 4, can be ascertained the history of the condition or conditions under measurement; the operating mechanism for platen 5 or equivalent is so phased that the printing of each symbol S occurs during that part of aforesaid cycle during which shaft 2 is at rest, 1. e. not during the time when earns 39 may be resetting the driving clutch member 35 to neutral.

When it is desired that the recording apparatus be suited for accurate measurement even under conditions where it is subjected to sudden and violent changes of position incident for example to climbing, diving or inverted flight of an aeroplane, it is preferred the disc I and slidewire I2 and applied to the grids of tubes 43, 4: preferably Thyratrons, in whose output system is included a reversible motor 44 directly coupled to shaft 2 or preferably, Fig. 3, to disc 45 rigidly connected to disc I and the supporting drum 46 of slidewire II. The direction of rotation of motor 44 depends upon the phase of the voltage applied to the grids or control electrodes of tubes 43, 43 which in turn depends upon the sense of unbalance of network M.

In avoidance of overshooting, the measuring network M may include a voltage of magnitude varying as a function of the speed of rebalancing and of sense opposed to the unbalance; more particularly, the generator 41 driven from or comprised in motor 44 is connected effectively in series with the slidewire 46 and thermocouple l4, or like condition-responsive device, to oppose the unbalance of their voltages during adjustment of the slidewire.

With such arrangement, the time required to re-balance the network is so short that as many as 30 different symbols may in series be printed upon sheet 4 within each half-minute each of the 30 symbols being printed while disc l is at rest or substantially so and indicating the response of a thermocouple, pressure-responsive or equivalent device.

All of the apparatus of Fig. 2 except the condition-responsive devices l4 and the conductors thereto may be contained in a single housing. When the apparatus is installed in an aeroplane, the various condition-responsive devices may in clude thermocouples for measurement of motor temperatures, pressure-responsive and flow-responsive devices for measurement of fuel and lubricants, air-speed, structural stresses, and other conditions of significance in test or normal flight.

Referring now to Figs. 4 to 7, the inking pad or ribbon l and the record sheet 4 are both in front of disc. I. At suitable intervals, the sheet 4 is pressed against disc I by platen 5 so that upon the front face of sheet 4 appear symbols S and S,

. may be formed to provide, or have attached therebe adjusted by a relay system, Fig. 2, of the gen- Y eral type disclosed in aforesaid Williams patent and in his copending application Serial No.

457,845, now Patent No. 2,367,746, of which it is characteristic no galvanometer or equivalent deflection instrument is used.

Briefly, when the measuring network M, Fig. 2, including a condition-responsive device l4 and slidewire I2 is balanced, the variation of resistance 40, for example a carbon-button microphone, by the alternating-current vibrator 4| has no effect upon the output of the amplifier system A in whose input system is included an impedance 42 also common to the measuring network M. When, however, the network M is unbalanced, the variation in resistance 40in effect modulates the uni-directionalunbalance current; the alternating current component thereof is amplified to, a suitable raised index for printing an arrow or like index mark S adjacent each thereto presented and reproduced portion of scale 3.

shown, the sheet 4 is substantially wider than required for printing of the row of symbols S, and the major width of the sheet is utilized in association with a stylus or pen 48. The pen carriage is connected, as by an endlessloop 43A of cord to a drum attached to shaft 2 (not visible in Figure 4) to which the slidewire drum and disc I are attached, all as more clearly appears for example in Letters Patent 2,074,117 to Ross.. Because of inevitable lost motion between shaft 2 and pen 48, the points of the curve traced by pen 43 do not precisely correspond with the varmisalignment of the sheet 4 or to its changes in dimensions with variation of ambient conditions, it is provided with two series of specially shaped holes; the holes 49 near the left-hand margin,

Fig. 4, are elongated in direction normal to the direction of feed of the sheet and are of width, measured in aforesaid direction of feed, closely corresponding with the diameter of pins 50, or equivalent, extending outwardly from endless belt or chain 5| which passes over rolls 52, 53; the holes 54 somewhat beyond the right-hand limit of travel of pen 48, but to the left of the area reserved for printing of the symbols 5 and S, are elongated in the direction of feed of the sheet and snugly receive correspondingly shaped pins 55 extending outwardly from a second endless belt or chain 58; less desirably, the belts or chains BI and 56 may be omitted and the pins 50 and 55 attached to the peripheries of rolls 52 and 53.

The pins 50 and 55 both transmit motion to the sheet 4 and co-operate in maintaining the transverse or'time division lines 80 of the sheet parallel to the path of movement of the stylus or pen 48; the relative shapes of pins 50 and slots 49 permit the sheet to expand or contract transversely without buckling or wrinkling whereas slots 54 and pins II are so relatively shaped the "high end of the scale formed by the vertical or longitudinal lines II or sheet 4 is maintained in proper position with respect to the limit of movement of pen 48 in the "hi h" direction. In furtherance oLthis end. the belt 56, at least in the region or its travel adjacent the path of movement of pen 48, is received by guides I1 comprising members projecting from the front face of plate 58 in'i'ront of which sheet/4 passes and which is cut away or notched at 59 to allow platen Bto press sheet 4 against scale 30f disc I.

What I claim is:

1. Apparatus for recording on a record sheet instantaneous magnitudes of a condition comprising an element movable to positions corresponding with instantaneous magnitudes of said condition, a stylus in contact with said record sheet to produce a continuous graph of instantaneous magnitudes corresponding to the positions assumed by said element, printing means intermittently operable into contact with said record sheet to record an instantaneous value corresponding to the graph value then being recorded by said stylus, means permanently connecting said element, said stylus, and said printing means to drive them in either direction in accordance with the movements of said element. to produce on said record sheet said continuous raph, and to produce a movement of said printing means, and means for intermittently operating said printing means to effect printing.

2. Apparatus for recording on a record sheet instantaneous magnitudes of a condition comprising a balanceable measuring circuit having a circuit-element therein movable to positions corresponding with instantaneous magnitudes of said condition, a stylus in contact with said record sheet to produce a continuous graph of instantaneous magnitudes, printing means intermittently operable into contact with said record sheet to record an instantaneous value corresponding to the graph value then being recorded by said stylus, means permanently interconnecting said adjustable circuit-element, said stylus,

and said printing means and operablein response printing. A

IRVING M. BTMN. 

